Hologram duplication method

Abstract

A hologram duplication method is disclosed which makes it easy to duplicate a large number of holograms from a volume-recorded hologram, particularly from a hologram recorded in a recording medium of the disk type or the card type. N card type master recording media are prepared, and data pages are individually recorded on the N disk type master recording media without being multiplexed by changing the angle of a reference light beam among the N disk type master recording media. Thereafter, the data page recorded on each of the disk type master recording media is recorded on a common disk type duplication recording medium so that the data pages are N-multiplex recorded finally on the disk type duplication recording medium.

Description

BACKGROUND OF THE INVENTION [0001] This invention relates to a hologram duplication method for duplicating a hologram recording medium in which data pages are multiplex recorded in accordance with an angle multiplexing method. [0002] In recent years, a holographic technique has been developed rapidly in order to place a holographic memory into practical use, which attracts attention as a very promising candidate for a storage which is competitive with optical disks of the next generation and the next next generation. A hologram recording and reproduction system which makes use of a hologram technique to record and reproduce a large amount of data has been proposed and is disclosed, for example, in “Holographic data storage”, IBM J. RES DEVELOP, Vol. 44, No. 3, May 2000. [0003] Such a hologram recording and reproduction system as described above uses a method called multiplex recording in order to achieve high density recording. The multiplexing recording records a large number of in...

AI Technical Summary

Benefits of technology

[0008] It is an object of the present invention to provide a hologram duplication method which makes it easy to duplicate a large number of holograms from a volume-recorded hologram, particularly from a hologram recorded in a recording medium of the disk type or the card type.

[0014] In the hologram duplication methods, for example, when a data page (master hologram) recorded in a holographic form on a disk type master recording medium is duplicated on a disk type duplication recording medium disposed in the proximity of the disk type mater recording medium, for example, N card type master recording media are prepared. Then, the data pages are individually recorded on the N disk type master recording media without being multiplexed by changing the angle of a reference light beam among the N disk type master recording media. Thereafter, the data page recorded on each of the disk type master recording media is recorded on the common disk type duplication recording medium so that the data pages are N-multiplex recorded finally on the disk type duplication recording medium. Thus, a large number of duplicates of a volume-recorded hologram, particularly of a hologram recorded on a disk type recording medium or a card type recording medium, can be produced readily.

[0015] With the hologram duplication methods, a conical light beam or an obliquely incoming light beam is irradiated upon the disk type or card type master recording medium such that interference fringes between signal beam produced by diffraction of the conical light beam or obliquely inputting light beam by the disk type or card type master recording medium and the conical light beam or obliquely inputting light beam passing through the disk type or card type master recording medium are recorded collectively on the disk type or card type duplication recording medium. Consequently, a large number of duplicates of a volume-recorded hologram, particularly of a hologram recorded on a disk type recording medium or a card type recording medium, can be produced readily.

Problems solved by technology

However, a conventional emboss type duplication method of the surface roughness transfer type cannot duplicate a volume-recorded data page (hologram).

Further, in contact copying of a conventional type, since a parallel light beam is used, it is difficult to produce a reference beam for use upon duplication which has a same wavefront as that of a reference beam used upon production of a master disk.

Particularly it is difficult to reproducibly duplicate holograms recorded in a disk type recording medium.

Further, a master disk recorded data bit by bit from a volume-recorded hologram using a conical beam by a method disclosed in U.S. Published Application No. 2003 / 0161246 cannot be produced.

Therefore, it is still impossible to reproducibly duplicate volume-recorded holograms.

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